Scientists Scramble to Blunt Risk of Insecticide-resistant Malaria Mosquito Spreading in Africa

An invasive, malaria-carrying mosquito resistant to all insecticides is spreading faster and farther across Africa than scientists feared, threatening urban areas where malaria has not been a major threat. A genomic analysis of Anopheles stephensi, using specimens from 10 countries, found genetic resistance to all chemicals used in spraying campaigns, according to a study led by Tristan Dennis of the University of Queensland, published in the journal Science. The mosquito, which arrived in Djibouti over a decade ago, has pushed westward to Ghana and south through Kenya, thriving in cities and dry seasons.

Experts say it is too late to eliminate or contain it, and it could become a grave problem in megacities like Lagos and Kinshasa, each home to about 20 million people. "We've not had to worry about malaria in urban settings, said Dr. Eric Ochomo, head of entomology for the Kenya Medical Research Institute. Scientists are scrambling to find ways to blunt the risk. "The last couple of years there’s less talk of, ‘We really need to contain this invasion,’ because everyone who knows what’s what realizes that genie is completely out of the bottle, said Dr. Ochomo.